The OLED (Organic Light-Emitting Diode) display is a new type display technology developed in the middle of the twenty century, and possesses many advantages of ultra thin, all solid state, active luminescence, fast response speed, high contrast, no visual restriction, wide work temperature range, low power consumption, low cost, strong seismic capacity and possibility of flexible display, and will become the main stream of the next generation of flat panel display. Because of the excellent performance and the huge market potential, many factories and scientific research institutions in the worldwide have invested in the production and research of the OLED display panel.
However, due to the vibration tape and the inhomogeneous broadening effect, either for the organic small molecules or high polymer luminescent material, the spectral halfwidth is generally larger than 80 nm. Therefore, the usage ratio is very low in the color display manufactured with synthesis of the red, green, blue, three primary colors. For manufacturing the OLED display panel with narrow-line emission, people change the structure of the OLED display panel, and manufacture the Fabry-Perot (F-P) optical micro cavity of the OLED display panel to acquire the high brightness narrow-line emission. The optical micro cavity does not only realize the narrow-line emission but also significantly enhance the intensity of emission relative to the element of micro cavity structure. The regular F-P optical micro cavity structure requires two reflective mirror surfaces, which generally employ metal-metal structure. Therefore, the micro cavity total optical distance of the F-P optical micro cavity structure is restricted by the thickness and refractivity of the organic film layer in the OLED display panel, and the micro cavity total optical distance is shorter. It is difficult for the insiders to increase the micro cavity total optical distance by adjusting the organic film layer in the OLED display panel.